You sure that you do able to click a sell order? its impossible for you not to get the tokens if you purchased a token with btc. would you mind on posting a screenshot? so that we would able to know on what is really happening or the situation you are experiencing now., having visuals would be a great help on identfying.
Actually i ever heard same problem like this has been posted by other people too. He is having problem with altcoin buying not selling.
I used btc to buy altcoin but btc lost, altcoin not in my wallet. It is considered lost?
It's indeed lost, more likely it's disappeared. Contact them by sending a support ticket but i don't know when you will got a reply.